This invention relates to fancoil assemblies.
Fancoil assemblies have a heat exchange unit through which air is blown or sucked by means of a fan. The heat exchange unit takes the form of a finned, coiled pipe through which a fluid, such as water, is pumped. When the assembly is used to provide heating, the fluid supplied to the coil is heated; when cooling is required, the fluid is cooled. Typically, the heat exchange unit is of rectangular shape and section, and is arranged such that air flows through the exchange unit at right angles to its length and perpendicularly to its largest face. The heat exchange unit is mounted in an outer casing, which acts to channel air to and from the exchange unit. Preferably, the arrangement of the exchange unit in the casing is such that the maximum amount of air entering the casing flows through the heat exchange unit and the minimum amount flows around it. The heat exchange unit usually sits above a drain tray so that condensation is collected and channelled out of the casing through a suitable conduit for discharge.
The drain tray provides a space below the heat exchange unit into which condensate can flow. In conventional assemblies, this space can also provide a path for air flow under the heat exchange unit, leading to several potential problems. Firstly, the overall efficiency of heat transfer to or from air flowing through the fancoil assembly is reduced because a proportion of the air can by-pass the heat exchange unit. Secondly, the lower resistance to air flow under the heat exchange unit leads to a high velocity compared with air flowing through the exchange unit. This high velocity air flow can blow collected water out of the drain tray leading to leakage problems. The flow of air under the heat exchange unit can also create an elevated pressure below the heat exchange unit that reduces the rate of drainage of condensate from the heat exchange unit into the drain tray. This can cause an accumulation of water within the heat exchange unit, leading to inefficiency in heat transfer. The water accumulated in the heat exchange unit may also be blown out by air flowing through it.